Their math was wrong, but not in a way we can fix without a re-build of the driver.
Which might be fine for a handful of developers but isn't much help to the world full of Kindle owners.

The problem is that for my graphics code to continue to support all firmware versions for "all eink kindles" in both main and diags modes, I will have to compensate for this "math glitch", and then again in another way if and when they get around to fixing it in future firmware. Hopefully they will not do the "two incompatible ioctl structures with the same name" problem again like they did with 5.0.x and 5.1.x. Yuck...